Nirvana Enterprise Manager - Modifying Clusters

Introduction

The Nirvana Enterprise Manager enables you to modify clusters. By 'Modify' we mean, add new realms to the cluster or remove existing cluster members. Adding new realms is done by first of all ensuring that you have connected to the realm you wish to add. Removing realms is done simply by selecting the realm you wish to remove from the cluster. This will be discussed in more detail further on. If for example, i have a cluster with 2 realms, and i wish to add a 3rd realm to the cluster, i can do so. Similarly, if i have a cluster with 3 (or any number of realms) and i wish to remove a realm from the cluster, this is also possible.

Adding Cluster Members

In order to add a realm to a cluster, you must first ensure that you have created a cluster. Once you have a cluster, then also ensure you have connected to the realm you wish to add to your cluster. Select the cluster node from the namespace and right-click on the node. This will present you with a pop-up menu. Select the menu item labelled 'Modify Cluster Members'.

The dialog this presents you displays the current members of your cluster as well as any realms you are not connected to that are not cluster members. This dialog is shown below:

The dialog shows the name of the cluster, a list of non-cluster member realms (showsn as a list on the left hand side), and two lists for member realms, one showing member realms that can be elected master realm, and one showing member realms that cannot be elected master.

As you can see from the above example, currently there are 2 realms within the cluster 'productioncluster', and both can be elected master. There is 1 realm that is not in the cluster called 'productionslave2'.

Double-clicking on any non-member realm, or selecting it from the list and clicking the 'Add' button will enable you to add the realm as a member. You are given the choice as to whether the selected new member can be elected master within the cluster or not. This dialog is shown below:

Selecting the 'Yes' button will add the realm to the masters list, whereas no, will add the realm to the non-masters list.

When you have added the realms you wish to add as cluster members, click on the button labelled 'OK'. This will add the realm to the cluster. All cluster channels and queues will also be created on the new realm once the realm has successfully been added to the cluster.

Removing Cluster Members

Removing cluster realms is achieved by again selecting the cluster node, right-clicking on the node and choosing the 'Modify Cluster Members' menu item. This presents the same dialog as shown above.

To remove a realm, double-click on thre realm from either the masters list or non-masters list or select the realm and click the 'Remove' button. This will remove thre realm from the list and add it back into the non-members list.

Clicking on the button labelled 'OK' will then prompt you to answer a question. This question allows you to select one of 2 options:

• Delete all cluster wide channels and queues from each the removed realm members
• Convert all cluster wide channels and queues to local within the removed realm members

Choosing to delete all cluster channels and queues will not remove any locally created channels, only those created for the cluster within the realms you are removing.

Choosing to convert each one to local, will keep any data that may be contained within the cluster channels or queues for the realms you wish to remove.

Adding and Removing Cluster Members

Cluster members can be added and removed in the same operation. For example, if i have a cluster with realm1 and realm2 but i want to remove realm2 and add realm3, i would simply deselect realm2 and add realm3 from the modify members dialog. The Enterprise Manager will work out which realms to add and which to remove for you and perform the necessary channel conversion and deletions you choose.